Searching for alien technological signatures is getting a high-tech upgrade – Big Think
Searching for alien technological signatures is getting a high-tech upgrade – Big Think
By Tony Reichhardt, Dirk Schulze-Makuch | Published: 2025-06-03 19:09:00 | Source: Hard Science – Big Think
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In a galaxy teeming with possibilities Habitable planetsIt is reasonable to speculate that other spacefaring civilizations exist, and perhaps even that some of them, or their robotic probes, have already reached Earth. Interstellar distances are daunting, yes, but if travel time doesn’t matter — either because the aliens are non-biological robots or because they hibernate during the flight (some cicadas, for example, sleep 17 years underground and then emerge for a few months) — the possibility of extraterrestrial visitors cannot be ruled out.
This raises an obvious question: as Physicist Enrico Fermi famously asked, “Where is everyone?” Despite thousands of UFO/UAP sightings in the past 80 years alone, there is still no generally accepted evidence of alien spacecraft arriving on Earth.
It’s not like we didn’t look. Any number of space telescopes and cameras may have spotted an incoming spacecraft approaching us. Ground-based telescope networks It can detect objects as small as 10 centimeters in size Far from geosynchronous orbit (22,000 miles high). In recent decades, NASA-funded early warning systems, such as the Catalina Sky Survey and the Asteroid Impact Last Warning System (ATLAS), have been constantly monitoring asteroids that might threaten Earth. ATLAS can detect a small asteroid (about 20 metres) after several days, and a 100-meter asteroid several weeks later.
Every now and then, these sentinels mistake one of our probes for an asteroid. In 2020, for example, Catalina stated sincerely An object moving in space, presumed to be another flying rock, was quickly identified as… The BepiColombo spacecraft Make a close approach to the ground.
But so far, no space probe has spotted any. Despite early speculation that the intrusive object called ‘Oumuamua, which was discovered in 2017 – and remains one of only two large objects known to have arrived from outside our solar system – might be artificial, The consensus is that it’s just another space rock.
Vera C. Rubin Observatory
However, our ability to detect such interstellar visitors is about to take a huge leap. this summer, Vera C. Rubin ObservatoryThe telescope, one of the most eagerly awaited telescopes ever, is set to see its “first light” on a remote mountaintop in Chile. Designed more than a quarter-century ago as the Large Synoptic Survey Telescope, or LSST, Rubin’s mission, as the original name suggests, is to capture images of the entire southern sky at high sensitivity, using the largest digital camera ever built. Most importantly, it will repeat its scan of the sky every three to four nights for at least a decade.
The Rubin Observatory at Cerro Pacón in Chile stands against a sky full of star trails in this long image of the night sky. (Credit: Hernan Stockbrand)
Like any major observatory, it will address practically every problem in astronomy, from black holes to dark matter to Earth-threatening asteroids, whose position against the stellar background will change from one survey to the next. Over the next decade, Rubin is expected to discover millions of new objects, generating a staggering 20 terabytes of data every night. In the first month of the survey alone, the number of known small objects in our solar system could double, leading to asteroids being discovered at much farther distances than ever before.
Estimates of how many such objects might come from interstellar space vary widely. We only have two examples so far, and their discovery will depend on the material they’re made of, the shape of their orbits, how bright they are, and other factors. Some researchers predict that Robin will only see one of these events each year. Others believe it could be up to one per week. Either way, Robin should find many more interstellar objects than the two we know today.
Distinguishing natural from artificial
But how can we distinguish between natural objects – such as ‘Oumuamua – and actual spacecraft? After all, these can range from massive motherships, like the one in these Close encountersTo small probes like Voyagers, which we launch into interstellar space with our 20th century technology.
It’s a difficult problem. James Davenport of the University of Washington is among those who have done so There is speculation about how the Rubin Observatory, with its unprecedented power, may be able to detect the “technological signatures” of aliens. Including spacecraft. Natural objects such as comets that enter the solar system from interstellar space usually follow a hyperbolic orbit (different from the elliptical orbit around our Sun). In a timeline of Rubin snapshots taken every three nights, this would appear as a series of dots on the stellar background, which astronomers can piece together to extrapolate the entire object’s orbit. The path may show slight deviations here and there, due to everything from the pressure of sunlight to the release of gases if the objects resemble comets. However, the path should appear smooth and predictable overall.
But, says Davenport, “if they make a right turn, or if they make a very unusual movement,” that could indicate some kind of pushing or steering by an artificial probe. Astronomers should be able to detect these “non-gravitational accelerations” in the Rubin data, provided they are not so extreme that Algorithms are being developed to examine all that information Having difficulty recognizing notes from Robin’s successive shots They belong to the same organism.
Even with Robin’s exquisite sensitivity (up to level 27), small interstellar objects will still appear only as featureless specks. What would distinguish an alien spaceship from a comet? Perhaps a particularly strange spectral profile? Several objects flying in formation (assuming those objects aren’t just pieces of broken rock)? It’s hard to say. No one has ever seen an alien spaceship coming.
As a kind of test case for how to identify a small, distant artificial object in space, Davenport considered it Tesla vehicle Which SpaceX launched as a dummy payload for its Falcon Heavy rocket in 2018. Currently, the red roadster is orbiting in an elliptical solar orbit that reaches just beyond Mars. Davenport once thought it might stand out in Rubin’s data as a technological signature, but his latest models leave him unsure. For one thing, the cherry red paint marking it as unusual may have faded. In fact, small artificial objects like Tesla would pose a difficult observational challenge for any telescope. Take our Voyager spacecraft, which we know will pass other star systems one day in the distant future. Unless a similar probe sent by an alien civilization comes very close to us — say, within Saturn’s orbit — “even in the Robin era, we might not notice it,” says Davenport.
But we won’t know what the new telescope is capable of until it’s operational, and it may surprise us. Other observatories may join the search as well. In the 2019 paperBrian Lackey of the Breakthrough Listening Initiative at UC Berkeley has suggested that mirror-like flashes from light sails or flat surfaces on artificial spacecraft may appear as bright, fleeting light sources in current and future sky surveys. Suggest it Argus Matrixplanned to be installed in the mountains of North Carolina, may be ideal for this type of research. Although it is not as sensitive as Robin, it will scan the sky much more quickly, with a “cadence” of minutes rather than days.
So the search for alien spaceships is about to go up a notch. We will soon have our best chance yet of spotting anyone or anything that may be in our path. Of course, it’s entirely possible that there isn’t they There at all. Or if they came from the north, the south-facing Rubin telescope wouldn’t see them. Or if they are equipped with a science fiction staple, an anonymity device (No fair!), will be invisible. Or maybe they’re so advanced that they’re manipulating spacetime in a way we don’t understand, and they don’t even need an actual spaceship.
In this case, let’s just hope they’re friendly.
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